辽宁眼前山铁矿元素地球化学特征与沉积古环境研究

辽宁眼前山铁矿位于鞍山地区南北向和东西向铁矿构造变形带的复合部位,为鞍山地区鞍山式铁矿床的典型代表。本文对眼前山铁矿的岩石学、矿物学进行了研究,对该区铁建造和围岩的主量和微量元素地球化学进行了分析。该区铁建造以条带状为主,少量为块状,其顶底板围岩及矿体夹层主要为太古宇鞍山群千枚岩。主量分析结果表明,铁矿石主要由Si O2和铁的氧化物组成,Al2O3含量较低,LOI较大。矿石微量元素分配曲线属于右倾型,强不相容元素和大离子亲石元素富集,具有显著的Eu正异常,是海底高温热液(300℃)与海水混合的结果,表明了该区BIF形成与海底热液活动关系密切。该区BIF中富集重稀土元素,Y/Ho大于26,La和Eu具有正异常。由于缺少陆源碎屑物质,要形成稳定的条带状构造,推断该区的BIF形成于海水深度大于200 m的浅海环境,形成机制应该是富含铁的海底热液运移到相对浅水区发生氧化沉积所致。通过A-C-FM原岩恢复,结合Zr/Ti O2-Ni图解可知千枚岩为变质沉积岩;Sm/Nd比值也显示了沉积岩的特点。该区千枚岩中Th的变化范围为7.9×10-6~22.5×10-6,平均为15.8×10-6;La的变化范围为17.9×10-6~71.7×10-6,平均为38.4×10-6;La/Sc的平均值为2.3;Th/Sc的平均值为1.0;La/Th的平均值为2.4。这些值都接近大陆岛弧沉积岩特征。综合分析认为,眼前山铁矿成矿环境相当于弧后盆地。     

基于数值模拟与含水层垂向应力反演的静乐井水位异常分析

利用数值模拟与含水层垂向应力反演的方法,对降雨与河流荷载作用下静乐井区应力进行定量计算,并从区域应力场与同一构造区其他前兆测项变化特征对2种方法计算结果进行分析。数值模拟结果显示,降雨与河流荷载的共同作用使静乐井所在区域产生的最大垂向位移约为0.7mm,最大垂向应力约为30hPa;同时段静乐井-含水层垂向应力反演结果显示静乐井-含水层最大垂向应力约为79hPa;数值模拟与静乐井-含水层垂向应力反演结果均表明,静乐井水位高值异常与同时段降雨量增多、河流荷载效应增强关系密切,但2种结果存在一定差异。通过可反映井区应力场变化特征的山西地震带3级地震缺震和b值、穿过静乐井的GPS基线、地震矩释放、同一构造单元同时段其他前兆测项与静乐井水位高值异常对比等分析结果可知,2017年静乐井水位高值异常期间井区应力场存在显著异常,推测静乐井水位高值异常除受降雨与河流荷载作用的影响外,也可能受构造活动增强的影响。     

Structural analysis and interpretation of the surface deformation associated with the Ning’er,Yunnan Province,China <Emphasis Type="Italic">M</Emphasis><Subscript>S</Subscript>6.4 earthquake of June 3, 2007

The seismogenic fault and the dynamic mechanism of the Ning’er, Yunnan Province M_S6.4 earthquake of June 3, 2007 are studied on the basis of the observation data of the surface fissures, sand blow and water eruption, landslide and collapse associated with the earthquake, incorporating with the data of geologic structures, focal mechanism solutions and aftershock distribution for the earthquake area. The observation of the surface fissures reveals that the Banhai segment of the NW-trending Ning’er fault is dominated by right-lateral strike-slip, while the NNE-trending fault is dominated by left-lateral strike-slip. The seismo-geologic hazards are concentrated mainly within a 330°-extending zone of 13.5 km in length and 4 km in width. The major axis of the isoseismal is also oriented in 330° direction, and the major axis of the seismic intensity VIII area is 13.5 km long. The focal mechanism solutions indicate that the NW-trending nodal plane of the Ning’er M_S6.4 earthquake is dominated by right-lateral slip, while the NE-trending nodal plane is dominated by left-lateral slip. The preferred distribution orientation of the aftershocks of M_S≥2 is 330°, and the focal depths are within the range of 3～12 km, predominantly within 3～10 km. The distribution of the aftershocks is consistent with the distribution zone of the seismo-geologic hazards. All the above-mentioned data indicate that the Banhai segment of the Ning’er fault is the seismogenic fault of this earthquake. Moreover, the driving force of the Ning’er earthquake is discussed in the light of the active block theory. It is believed that the northward pushing of the Indian plate has caused the eastward slipping of the Qinghai-Tibetan Plateau, which has been transformed into the southeastern-southernward squeezing of the southwest Yunnan region. As a result, the NW-trending faults in the vicinity of the Ning’er area are dominated by right-lateral strike-slip, while the NE-trending faults are dominated by left-lateral strike-slip. This tectonic framework might be the main cause of the frequent occurrence of M_S6.0～6.9 earthquakes in the area.     

网箱养殖大黄鱼生长特性的研究

对宁德地区网箱养殖大黄鱼(Pseudosciaena crocea)生长特性进行了研究。测定了780尾大黄鱼25个月龄的各项生长数据,体长变幅为20.5~320.0 mm,体质量变动范围为0.281~555.5 g;生长指标显示,体长生长指标为0.208~2.123,体质量生长指标为0.529~47.579;肥满度波动范围为1.74%~2.37%;肝指数变动范围为0.92%~2.07%;鳔生长指数为1.08%~1.85%;雌鱼性腺成熟系数为0~10.04%,而雄鱼则为0~2.27%。以Keys氏公式W=aLb,拟合25月龄养殖大黄鱼的体长(L)与体质量(W)的关系式为:W=0.0195 L 2.9775(R2=0.9959),其中b≈3,即此生长阶段的网箱养殖大黄鱼生长均匀,为等速生长类型;体质量生长呈幂函数生长,其回归方程为:y=1.8617x1.8099(R2=0.9931)。体长Y(cm)与养殖时间X(月龄)的生长呈二次多项式关系,其回归方程为:y=?0.0259x2+1.7125x+4.1534(R2=0.989)。